Project Summary The goal of this application, submitted in response to RFA-MH-20-110, ?Secondary Data Analysis to Examine Long-Term and/or Potential Cross-Over Effects of Prevention Interventions: What are the Benefits for Preventing Mental Health Disorders?,? is to leverage data from existing prevention intervention trials with longitudinal follow-up to answer key questions about the long-term impacts of prevention intervention trials. Aggregating these data sets will allow for novel secondary data analyses which will enhance our understanding of intervention impacts on 1) suicidal behaviors, 2) depression and anxiety symtoms and diagnoses, and 3) psychosis symptoms. There is a pressing need to link and harmonize data from primary school universal prevention trials with longitudinal follow-up including suicide (ideation, attempt, and death) and mental health diagnoses (including depression, anxiety, and psychosis) to understand how changing trajectories of key risk factors for these outcomes (social support, deviant peer affiliation) prevents the occurrence of the negative outcomes described above. Many of the existing prevention trials are not large enough to find an impact on rare outcomes, and even less powered to explore treatment effect heterogeneity. Our objective is to link and harmonize data from six randomized controlled trials with preventive interventions focused on reducing disruptive and aggressive behavior in early childhood to understand the long-term impacts of universal prevention programs on key outcomes in early adulthood including suicidal behaviors, depression and anxiety symtoms and diagnoses, and psychosis symptoms. Data will be utilized from the Fast Track Project (Bierman et al., 2004), the Good Behavior Game trials (Kellam et al., 2008; Ialongo et al., 1999; Ialongo et al., 2019), the SAFEChildren Trial (Tolan et al., 2004), and the Linking the Interests of Families and Teachers Study (LIFT; Eddy et al., 2000; Reid et al., 1999). Our hypothesis is that with a harmonized dataset, there will be sufficient power to identify prevention program impacts into adulthood and as such we will find impacts of these programs beyond what was originally targeted. Our rationale is that with at least 10,000 participants across all studies, linkage and harmonizing data will allow for more complex, multifactorial, multi-level analyses to explore intervention impact on suicidal behaviors, depression and anxiety symtoms and diagnoses, and psychosis symptoms as well as potential mediators and moderators of impact.